Comments on: Cleaner code in MATLAB part one of series http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/ <a href="http://www.mathworks.com/matlabcentral/fileexchange/loadAuthor.do?objectId=969735&objectType=author">Bob</a>, <a href="http://www.mathworks.com/matlabcentral/fileexchange/loadAuthor.do?objectId=1093599&objectType=author">Brett</a> & <a href="http://www.mathworks.com/matlabcentral/fileexchange/loadAuthor.do?objectId=1094142&objectType=author">Jiro</a> share favorite user-contributed submissions from the File Exchange. Sun, 22 Nov 2009 23:22:00 +0000 http://wordpress.org/?v=2.3.1 By: Nasser http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-6945 Nasser Wed, 05 Dec 2007 12:05:26 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-6945 Hi sebaa, Have u found a NSGA-II coded in matlab with binary code Hi sebaa,

Have u found a NSGA-II coded in matlab with binary code

]]> By: Nasser http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-6944 Nasser Wed, 05 Dec 2007 11:14:21 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-6944 Thank indeed for ur help but I'm looking for NSGA-II with binary coded (representation) the one that have u sent if real vector Thank indeed for ur help but I’m looking for NSGA-II with binary coded (representation) the one that have u sent if real vector

]]> By: Doug http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1429 Doug Mon, 11 Jun 2007 12:28:04 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1429 File exchange to the rescue: http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=10429&objectType=File File exchange to the rescue:

http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=10429&objectType=File

]]> By: sebaa http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1427 sebaa Sat, 09 Jun 2007 12:26:20 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1427 dear sir do you have a NSGA-II coded in matlab with binary code thanks dear sir
do you have a NSGA-II coded in matlab with binary code

thanks

]]> By: DanK http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1340 DanK Thu, 21 Dec 2006 14:14:30 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1340 Loren, Thanks for the answer. From that response it does sound like the complicated, ugly, code probably does save a lot of memory allocation, at least when you are dealing with large sets of data. As a side note, it would be interesting if profiler had a mechanism which allowed one to know what part of an expression was using time, rather than just line by line. I'm guessing that that is a far from simple modification, however. Dan Loren,
Thanks for the answer. From that response it does sound like the complicated, ugly, code probably does save a lot of memory allocation, at least when you are dealing with large sets of data.

As a side note, it would be interesting if profiler had a mechanism which allowed one to know what part of an expression was using time, rather than just line by line. I’m guessing that that is a far from simple modification, however.
Dan

]]> By: Loren Shure http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1337 Loren Shure Wed, 20 Dec 2006 18:23:06 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1337 Dan- With respect to temporary expressions, MATLAB cleans up or reuses the memory as it goes. So, for example, assuming all variables and sizes are suitable for this expression (a+b)+(c+d) We end up with 2 intermediate temporaries (not 3). The temporaries start off being for the expressions in parentheses. And when those subexpressions are added, MATLAB is smart enough to know that it can overwrite one of the temps with the final value. So at most here, you have only one extra temporary). There are some extra considerations that MATLAB does for expressions like A = A + 1; when this is inside a function M-file. I will be writing about that soon in one of my upcoming blog articles. --Loren Dan-

With respect to temporary expressions, MATLAB cleans up or reuses the memory as it goes. So, for example, assuming all variables and sizes are suitable for this expression

(a+b)+(c+d)

We end up with 2 intermediate temporaries (not 3). The temporaries start off being for the expressions in parentheses. And when those subexpressions are added, MATLAB is smart enough to know that it can overwrite one of the temps with the final value. So at most here, you have only one extra temporary).

There are some extra considerations that MATLAB does for expressions like

A = A + 1;

when this is inside a function M-file. I will be writing about that soon in one of my upcoming blog articles.

–Loren

]]> By: DanK http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1336 DanK Wed, 20 Dec 2006 17:13:58 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1336 Doug, I'm thinking mainly of the extra time required in memory allocation and handling, when you are processing large volumes of data. What I am really unsure of here, is what memory usage MatLab makes for intermediate steps in complex computations. Is it allocating the memory just the same as it would if we assigned each intermediate value to a variable and then clearing that allocation at the end of the computation? If so then I would imagine you really don't lose much time. For reference I'm thinking about processing done on arrays that are, for example 20,000x25, which can definitely chew up a bunch of memory. Dan Doug,
I’m thinking mainly of the extra time required in memory allocation and handling, when you are processing large volumes of data. What I am really unsure of here, is what memory usage MatLab makes for intermediate steps in complex computations. Is it allocating the memory just the same as it would if we assigned each intermediate value to a variable and then clearing that allocation at the end of the computation? If so then I would imagine you really don’t lose much time. For reference I’m thinking about processing done on arrays that are, for example 20,000×25, which can definitely chew up a bunch of memory.

Dan

]]> By: Doug http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1335 Doug Wed, 20 Dec 2006 14:29:02 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1335 Dan and Nick, There are times when cryptic code code does give faster results. The profiler, as outlined in an earlier video helps to diagnose that. However, I think that sloppy code, like the kind in my original file, is rarely faster, simply harder to understand. Even if the clearer code were slower, the ease of understanding would outweigh most small performance gains in most situations. That being said, I think it is worth adding another video at the end to compare the two. My instinct is that their will be negligible difference in speed. Doug Dan and Nick,

There are times when cryptic code code does give faster results. The profiler, as outlined in an earlier video helps to diagnose that. However, I think that sloppy code, like the kind in my original file, is rarely faster, simply harder to understand. Even if the clearer code were slower, the ease of understanding would outweigh most small performance gains in most situations.

That being said, I think it is worth adding another video at the end to compare the two. My instinct is that their will be negligible difference in speed.

Doug

]]> By: DanK http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1334 DanK Mon, 18 Dec 2006 18:14:17 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1334 I have the same question as Nick. My solution has generally been to write the complicated code, and then provide the "simple" code as a comment, so that I don't have to give up speed. I also wonder about the merits of cluttering up the variable name space... Is this yet another case, "there is never really one size that fits all"? I have the same question as Nick. My solution has generally been to write the complicated code, and then provide the “simple” code as a comment, so that I don’t have to give up speed. I also wonder about the merits of cluttering up the variable name space… Is this yet another case, “there is never really one size that fits all”?

]]> By: Nick Cheilakos http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1330 Nick Cheilakos Sun, 17 Dec 2006 04:37:25 +0000 http://blogs.mathworks.com/pick/2006/12/13/cleaner-code-in-matlab-part-1-of-series/#comment-1330 We have a mess code but is efficient an we have a clean code but loses in speed. Which code we prefer? In your example which code is faster? The first or the clean version? ps: I know, that if we have clean code we can do debugging very easy.But i dont know if sometimes we earn something else We have a mess code but is efficient an we have a clean code but loses in speed. Which code we prefer?

In your example which code is faster? The first or the clean version?

ps: I know, that if we have clean code we can do debugging very easy.But i dont know if sometimes we earn something else

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